#header {
    background: var(--background-secondary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 12px;
    border-bottom: 1px solid var(--background-highlight);
}

#header-logo {
    display: flex;
    align-items: center;
    gap: 5px;
    font-weight: bold;
}

#header-logo img {
    max-width: 32px;
}

.header-button {
    color: var(--text-menu);
    background: transparent;
    margin: 0;
    padding: 4px;
    border: 0;
    outline: 0;
    display: flex;
    align-items: center;
    cursor: pointer;
    border-radius: 6px;
    transition: background-color 200ms ease, transform 200ms ease;
}

.header-button:hover {
    background-color: var(--background-highlight);
}

.header-button-placeholder {
    width: 32px;
}

@media (max-width: 48em) {

    html,
    body {
        height: 100%;
    }

    #split-pane {
        overflow: hidden;
    }

    #right-pane, #main {
        width: 100%;
        padding: 0;
    }

    #main {
        padding: 1rem;
    }

    #header .header-button svg {
        width: 32px;
        height: 32px;
    }

    #left-pane, #toc-pane {
        position: fixed;
        top: 0;
        bottom: 0;
        width: 80%;
        max-width: 300px;
        background: var(--background-secondary);
        transition: transform 200ms ease;
        z-index: 2;
        overflow-y: auto;
    }

    #left-pane {
        left: 0;
        transform: translateX(-100%);
    }

    #toc-pane {
        display: flex;
        right: 0;
        transform: translateX(100%);
        padding: 20px;
    }

    #toc-pane h3,
    #toc-pane #toc {
        display: block;
    }

    .menu-open #left-pane,
    .toc-open #toc-pane {
        transform: translateX(0);
    }

    body::before {
        content: "";
        display: block;
        position: fixed;
        top: 0;
        bottom: 0;
        left: 0;
        right: 0;
        background: rgba(0,0,0,0);
        pointer-events: none;
        transition: background-color 200ms ease;
        z-index: 1;
    }

    body.menu-open::before,
    body.toc-open::before {
        background: rgba(0,0,0, 0.6);
        pointer-events: auto;
    }

}